Feed-screw for rock-drills



' (No Model.)

W. A. KEYSER. FEED SGREWTOR ROUK DRILLS.

Patented Mar. 3,1896.

PHOTO *UTHO WASH UNITED STATES I PATENT OFFIZYE.

W'ILLIAM ALMOND KEYSER, OF GRANITE MOUNTAIN, TEXAS.

FEED-SCREW FOR ROCK-DRILLS.

SPECIFICATION forming part of Letters Patent N 0. 555,604, dated March 3, 1896.

Application filed June 5, 1895. Serial No. 551,771. (No model.)

To all whom it may concern.-

Be it known that I, WILLIAM ALMOND KEY- SER, a citizen of the United States, residing at Granite Mountain, in the county of Burnet and State of Texas, have invented a certain new and useful Improvement in Feed-Screws for Rock-Drills, of which the following is a specification, reference being had therein to the accompanying drawings.

My invention relates to drills for the cutting or drilling of stone, and has for its primary object the taking up of wear in the wormscrews upon which such drills are usually mounted.

The type of drill to which I have reference is the well-known steam or pneumatic drill, in which the drill proper and its actuating engine or cylinder are mounted upon a heavy screw by which the drill is fed into the rock as it cuts its way. The impact of the rapidlysucceeding blows of the drill operate to rapidly wear the threads of the said screw, the result being that the cylinder soon begins to jump at every concussion, this jump being greater as the wear becomes more marked. The jumping of the cylinder and drill acts to relieve the force of the blow, acting, as it were, as a cushion,and in practice this becomes a great item in the efiiciency of the drill, as it will require from one-fifth to one-half more time to drill the same distance with a worn feed-screw than with one not worn. Moreover, the feed-screw must be replaced after a comparatively short life, this being a constant and considerable item of expense. My invention is, briefly, to so construct this feedscrew that it can be made to take up its own wear.

In describing my invention I will make use of the accompanying drawings, in which the same numeral will always refer to the same part.

Figure 1 represents a portion of the feedscrcw in common use upon the rock-drills described, with its crank and travel-lug operating the cylinder. Fig. 2 is a sectional View of my feed-screw, of which section Fig. 3 is a mate. Fig. 4: is a strip of thin metal. Figs. 5 and6 represent a packing-piece. Fig. 7 is an elevation of the upper portion of Fig. 3, of which same figure Fig. 8 is a top view. Fig. 9 is an elevation of the lower portion of Fig. 3 as seen at the back.

1 is a portion of the tripod used in steamdrills, upon which is mounted feed-screw 2,

with head 7, bearing 4, and crank 5, said screw operating travel-lug 3 of cylinder 6. This feed-screw 2 is cut in half upon its longitudinal line, one part, as shown in Fig. 2, being provided with threaded holes 8, and the other part, as shown in Fig. 3, having slots 9 registering with the said holes 8. The said slots 9 have surface recesses 10 upon the threaded face, in which are sunk the heads of screws 11, which engage holes 8 and bind the parts together, a thin piece of metal 12 being inserted to take up the loss of material in sawing the bolt into two parts. It will be 110- ticed that the part Fig. 3 of the bolt is only cut as far as the head of the feed-screw, leaving a shoulder into which is set a packingpiece 13 with nibs 14 entering recesses 16 in the top of the part Fig. 3. It will now be readily seen that by loosening the screws 11 and inserting packing-pieces 13 of varying thicknesses the respective parts of the feed screw Will be placed in differing relative 1ongitudinal positions, and that by this variation the feed-screw can be made to take up itself any wear there may be between it and the travel-lug 3 of the cylinder. By this means the threads of the feed-screw may be Worn almost through without replacing or resulting jump of the drill.

I am aware that in Letters Patent No. 166, 7 04 there is described a sectional nut or rack in a lathe-carriage adjusting mechanism, wherein a part of the said rack is moved by a screw to take up wear. This, however, is not applicable to a pneumatic or steam rock-drill, and is not esteemed as anticipating my invention.

Having explained my device and its working, what I claim is- 1. A feed-screw composed of a plurality of longitudinal sections combined with means for adjusting said sections in their juxtaposition, substantially as and for the purpose described.

2. A feed-screw for rock-drills, comprising longitudinal sections, set-screws for securing the said sections in their juxtaposition, and a packing-piece to secure the adjustment of the said sections, substantially as described.

In testimony whereof I affix my signature in presence of two Witnesses.

WILLIAM ALMOND KEYSER.

Witnesses:

L. D. LAWSON, D. W. WILSON. 

